In an antenna array several single antennas are grouped together to form a known pattern. Using a control unit connected to each of the individual antennas, the amplitude and the phase of the electromagnetic waves emitted by each antenna can be controlled in a way that the electromagnetic waves interfere with each other creating a planar wave with a defined propagation direction and desired properties. Such antenna arrays are also called plane wave converters (PWC) or phased arrays.
In order to ensure a precise control of the radiation of the antenna array, each antenna has to be calibrated with respect to its phase and amplitude, and a phase weighting calculation has to be performed for generation of a planar wave having the properties intended.
For calibration of known antenna arrays, the radiation pattern for each of the antennas has to be determined with a moveable measurement antenna in the near field for measuring the radiation pattern of each antenna. Alternatively, multiple stationary probes or measurement antennas are positioned in the far field for calibration purposes. The number of stationary probes has to equal the number of antennas in the array.
Therefore, calibrating an antenna array necessitates complex measurement equipment. In addition, calibration is time consuming under currently known methods.